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LMP8603: How to calibrate Voffset on Reduce Gain condition

Guru 18160 points
Part Number: LMP8603
Other Parts Discussed in Thread: LMP8601

Please let me know about idea for fixed Voffset on Reduce Gain condition, detailed information is below.


・Vs: 5V and Voffset: 2.5V

・On datasheet page-23, Rr is using digital potentiometer and adjust Gain. 

  But when Rr value (= Gain) is change, A2 input voltage also decrease, as a result LMP8603 can not output less than Voffset. 

・If change Rr to Capacitor, Vs/2 output was clear but higher Gain for customer request. 

・If change LMP8603 to LMP8601 and Increase Gain condition, maybe clear but occur layout change.


If there any idea for constant output referenced Vs/2, it is great helpful.

Best regards,


  • Hello Satoshi,

    We are looking into your issue now and will get back to you shortly.
  • Satoshi,

    The configuration on page 23 of the datasheet (also shown below) is for reducing the gain.  The default gain of the LMP8603 is 100V/V.  Any resistor tied to A1, A2, and ground like in the figure below, will lower the voltage at A2 and the overall gain of the LMP8603 device.  Below is a table that summarizes the gain trend with respect to Rr.  As for the output going less than the Voffset,  I suspect that your issue is you only have positive current flow across your shunt.  However, could you share a diagram of your circuit and the expected current conditions?  Also, what do you mean your output was 'clear' with capacitor?

    Figure 1

    Table 1

  • Hello Satoshi,

    I have not heard from you in a while. I presume your issue has been resolved. However if you do have any further questions, feel free to ask here or if it is about a different device in a new thread.